Many consumer products are packaged in granular or powdered form, such as for example, infant formula, flour, coffee, and sugar. Stock keeping units of granular or powdered form which are sold in volumes larger than one-time use amounts require specific packaging. Such packaging must be suitable for storage until first time use and must provide adequate storage at the consumer site between subsequent uses. Adequately storing the product throughout the consumption cycle requires packaging which prohibits waste and contamination, is strong and durable, and is convenient to the user.
Multiple-use containers for power products are typically constructed of polymers. Such materials are subject to many variables that adversely result in product components being produced that can vary beyond acceptable dimensional tolerance limits. Also, polymeric materials can render mis-shaped component profiles due to unexpected shrinkage and warping. These types of manufacturing problems are especially pronounced in containers formed from assemblies that incorporate more than one component, such as where a top or lid and a collar assembly are fastened to a bottom part or base of a container.
Still other users experience problems with prior art containers that are inadequate for use in circumstances where the ambient air pressure external to the container changes drastically so as to create a significant pressure differential between the sealed interior space of the container and the external, ambient atmosphere. For example, when a container is packaged at a facility at sea-level pressure, and then shipped to consumers located at higher altitudes, the container will have a higher internal pressure, which creates a pressure differential that can be significant. If the pressure differential is large enough, the container may become distended, making it difficult to stack and store, and may even experience a breach, leading to contaminated and wasted product. The opposite situation can occur when containers that are filled and sealed at a higher altitude are shipped to lower altitude users. Upon opening, ambient air can rush into the interior space of the container and contaminate the contents.
When a container having a pressure differential is opened, the contents may again spill due to the very rapid pressure equalization ejecting a cloud of powdered or other type of product contents. Attempts to overcome these disadvantages have included thicker walled containers, which increases weight and material costs, as well as round and cylindrical containers that may have higher hoop stress strength, but which are less efficient and convenient to stack and store on a shelf.
A container is needed that addresses the many issues surrounding prior art containers, and which most importantly offers new and innovative ways to prevent and/or minimize contamination, spillage, and waste of product contained in such containers. A more durable container is needed that incorporates improved rigidity and strength characteristics that can expand the range of acceptable dimensional tolerances and that can adapt to and more readily accommodate unexpected mis-shaped container component profiles.